The basic purpose of this collaborative research is to assess the efficacy, efficiency, and safety of two well-defined, short-term psychological approaches, Cognitive/Behavior Therapy and Interpersonal Psychotherapy, for treating non-bipolar, non-psychotic outpatient depression. The psychotherapies will be compared to a treatment demonstrated to be effective for this patient population, a tricyclic antidepressant medication. A pill-placebo condition is include to establish the adequacy of the antidepressant drug as a reference treatment. Outcome will be evaluated in terms of symptomatology, general clinical status, and social functioning and will be measured at various points during treatment, at termination and at several follow-up points. The study will be conducted simultaneously at several research sites, using a final common research protocol. The research has two phases, a Pilot Study and a Main Study. The purposes of the first phase include training of therapists in the different approaches, testing of patient selection criteria, evaluation of patient flow and assessment instruments, and piloting of actual use of the treatments by the therapists. The training and pilot phase will take two years and based on results of the Pilot Study, appropriate changes will be made in the design of the Main Study planned for a succeeding year.